#11: Wearing Baseball Caps Indoors
The baseball cap crossed from the stadium into everyday American life a long time ago. It now appears in airports, restaurants, offices, stores, and family photographs, often staying on from breakfast until bedtime. Traditional etiquette in many places still treats indoor headwear differently, especially inside churches, museums, formal dining rooms, and older institutions. Removing a hat once signaled respect, much like standing when someone entered or dressing carefully for Sunday dinner.

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